SEPTEMBER 6-7 - MINUTES OF MEETING 
7 
h, the probability that they will be correctly expressed, and a, the 
probability that they will gain access to their targets in the organism 
at risk. Numbers are assigned to the factors and the factors are multiplied 
to yield a number. Dr. Brenner states that it is important to recognize 
that if any of the factors can be assigned zero, then everything must be 
zero for that particular event. Dr. Gottesman stated that the scheme 
proposed by Dr. Brenner amounts to a more formal analysis of the issues 
that the RAC has been considering. For example, the "escape" aspect has 
been considered under "physical containment," the "reversion" and "transfer" 
aspects have been considered under "biological containment," etc. She 
said that Dr. Williams would be discussing data available on a number of 
the steps described in Dr. Brenner's scheme. She said that the basic 
question is whether the probabilities are sufficiently low to justify 
the proposed exemption. Procedures for handling exempt experiments are 
a separate issue. 
Dr. Novick stated that, at the beginning, the scientific community tried 
to conjure up all possible hazards and assumed that there were real 
hazards. He said that the thinking has became more and more realistic, 
and noted that Dr. Brenner's scheme has focused on pathogenicity for 
humans. He said that one cannot spend one's life worrying about hypothetical 
hazards. Rather, we are bound to deal with hazards when they surface. 
Dr. Campbell expressed concern about the aspect of selective amplification 
in some of Dr. Brenner's canonical experiments. He cited a canonical 
experiment involving an expressing purified cholera toxin gene on a 
conjugative plasmid carrying an antibiotic resistance determinant. 
While Dr. Brenner describes this as an experiment with a clearly defined 
hazard. Dr. Campbell said that he does not understand why the plasmid 
would have a selective advantage. Dr. Novick suggested that the RAC not 
deal with the individual examples, but rather deal with principles. 
Dr. Campbell said that he does not think that natural competition has 
been given adequate weight in Dr. Brenner's scheme. 
Dr. Williams then began the report and recommendations of the Working 
Group. He said that the Working Group had considered the specific exemption 
for E. coli K-12, as well as procedures which might be adopted for all 
classes of exempt experiments. He cited the limitations of the current 
formulation of the preposed exemption. He said that the basic question 
is whether the recent evidence is relevant and sufficient to justify the 
exemption. He called the RAC's attention to the references in item 708, 
and the papers by Freter, et al. , and Levy and Marshall in the Recombinant 
ENA Technical Bulletin (Recombinant ENA Technical Bulletin 2: 68-80, 
1979.) 
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